Cats sleep a lot. However, a new study, published in the journal Current Biology, reveals something cat owners may not notice: cats tend to sleep on their left side. And, conversely, if they sleep on their right side, the left side of their visual field is obstructed by their body. But then the question is, why do cats prefer the left side of their visual field unobstructed? For example, on whether the preference concerning which side cats sleep on is correlated to some other parameters, maybe less jumpy cats have less of this left-side preference.